Safety restraint for break-away wheel assemblies

ABSTRACT

A semi-trailer wheel restraint system having a bearing swivel and one or more cable sections and hub cab attachments for receipt into and through a hollow core of the trailer&#39;s axle. During a wheel bearing failure, the wheel restraint system keeps the loose wheel assembly near the end of the axle by anchoring it to the opposite-end&#39;s hub cap, thereby preventing a run-away wheel assembly and providing an operator of the truck an opportunity to safely stop the rig.

FIELD OF THE INVENTION

The invention generally relates technologies to prevent run-away wheelassemblies after a mechanical failure such as a wheel bearing failure onan over-the-road trailer.

BACKGROUND OF INVENTION

For the purposes of this disclosure, the term “hollow trailer axle”shall refer to any of a variety of axles employed on a variety of towedtrailers, such as over-the-road semi-trailers, tractor trailers, and thelike, as well as any other axle for a vehicle which is hollow throughits core.

FIG. 2 (not shown to scale) provides a functional, lengthwise cut-awayview of a generalized hollow trailer axle (200), which generallycomprises of a larger diameter center portion (202-202′), with a smallerdiameter hub portion (201, 201′) at either end. The hub portions andcenter portion are generally constructed of sections of high-strengthround metal tubes, such that the core of the axle from end to end ishollow. The transition between the hubs and the center portion mayinclude several steps, flares, and increments in order to receive andaxially-orient the components of the brake and wheel assemblies. Thehubs themselves may be parallel (straight) (as shown) or tapered. Hubsare typically provided with threads on the outside surface for receivingone or more spindle nuts.

FIG. 3 (not shown to scale) illustrates an exploded view of a generalizeset of components which are received onto a hub (201), aligned on thecenter (300) of the axle. Generally speaking, an inner bearing group ofcomponents (301′) is received onto the spindle (201), which mightinclude an inner bearing and a hub seal. Then, a brake system (302) anda hub with lugs (303) are received onto the spindle (201). These mayinclude an air disc brake (ADB) hub and rotor assembly, a standardservice conventional hub without a brake system, a cast spoke hubwithout a brake system, etc. Next, an outer bearing (301) is receivedonto the spindle (201), and secured by a spindle nut system (306). Aspindle nut system may include an inner adjusting nut with lock washer,set screw, star lock washer, and an outer jam nut; a castle nut washerwith castle nut and cotter key; or a one-piece spindle nut such as aStemco™ PRO-TORQ™ nut with a retainer ring.

After the spindle nut system is installed, a hub cap gasket and a hubcap (307) are installed to cover and protect the greased bearings, andto close the end of the hollow spindle (201) to the outside environment.The hub cap is typically secured by a series of small bolts around theperiphery of a mounting ring formed in the hub cap. Optionally, if thehub cap is provided with a hubcap oil fill port, a dust cap (308) issecured to the hub cap using a set of bolts, yielding an assembled hubassembly.

Subsequently, the wheel(s) (304, 304′) with tires (305, 305′) are passedover (around) the hub cap and dust cover to align mounting holes in thewheel(s) with the lug bolts on the hub (303), receiving the lug boltsthrough the wheel mounting holes. Lug nuts (500) are threaded onto thelug bolts, tightened to torque levels appropriate for the particularwheel, trailer, and load range, to yield a mounted wheel assembly, asshown in FIG. 4.

While the lug bolts, lug nuts, and their current torque levels arereadily inspected by a truck driver or repair technician, the state ofthe bearings is not without disassembly of these components. The innerbearings are essentially impossible to inspect without disassembly,which is a time consuming task. And, the re-assembly may lead to errorswhich were not originally present prior to the inspection effort.

When a wheel bearing (301, 301′) fails, the components of the assemblyshift off center (300), and it generally causes enough torque, heat andabrasion that the spindle nut system fails, so the wheels and tires(304, 304′, 305, 305′) with the still-attached hub (303) and brakesystem (302), as shown in FIG. 6, fly free of the axle assembly as asub-assembly (600), often at a high rate of speed (601), as shown inFIG. 5. Combining the speed (601) with the weight of the break-awaysub-assembly (600), which can weigh as much as 700 pounds, a verydangerous projectile is now loose and out of control. It can travel agreat distance before stopping, causing considerably property damage, aswell as injury and death to people and livestock.

FIGS. 2-5 are for general reference only, and represent the functionalcomponents of a typical trailer axle, hub and wheel system. In actualproducts, numbers of components, sizes, order of assembly, and names mayvary to some degree, while still being represented by thegeneralizations of these figures.

SUMMARY DISCLOSURE OF THE INVENTION

A plurality of exemplary embodiments are described for a semi-trailerwheel restraint system having a bearing swivel and one or more cablesections and hub cab attachments for receipt into and through a hollowcore of the trailer's axle. During a wheel bearing failure, the wheelrestraint system keeps the loose wheel assembly near the end of the axleby anchoring it to the opposite-end's hub cap, thereby preventing arun-away wheel assembly and providing an operator of the truck anopportunity to safely stop the rig.

BRIEF DESCRIPTION OF THE DRAWINGS

The description set forth herein is illustrated by the several drawings,which are not necessarily drawn to mechanical scale.

FIG. 1 illustrates an embodiment according to the present invention of awheel restraint system installed into a hollow axle of a typicalsemi-trailer.

FIG. 2 shows a lengthwise cut-away view of a generalized hollowsemi-trailer axle for reference understanding the disclosed embodimentsof the present invention.

FIG. 3 illustrates a plurality of generalized axle and wheel systemcomponents and sub-assemblies of a typical hollow semi-trailer axle forreference understanding the disclosed embodiments of the presentinvention.

FIG. 4 shows the components of FIG. 3 in an assembled and mountedconfiguration.

FIG. 5 depicts a typical failure mode following wheel bearing failurefor reference understanding the disclosed embodiments of the presentinvention.

FIG. 6 sets forth an exemplary embodiment of a wheel retainer systemaccording to the present invention.

DETAILED DESCRIPTION OF EMBODIMENT(S) OF THE INVENTION

The inventor of the present invention has recognized a problem in theart not previously recognized or addressed regarding prevention ofrun-away, break-away or fly-away semi-trailer wheels. Some of thesefailures are due to lug nut over-torquing and/or lug bolt stress andwear. To the degree that these elements can be readily visuallyinspected by a technician without significant disassembly andre-assembly, these failures can be minimized by enhanced maintenancepractices. However, the present inventor has recognized that the otherrun-away, break-away or fly-away semi-trailer wheels which due tobearing failures are much more difficult to prevent, and that existingtechnologies on the market are insufficient and/or ineffective for anumber of reasons. Therefore, the following structures are disclosedwhich are exemplary of the invention which is inexpensive, effective,and readily installed on existing hollow axle assemblies. While certaincomponents and certain dimensions and specifications may be disclosed,it will be recognized by those skilled in the art that certainsubstitutions may be made without departing from the spirit and scope ofthe present invention.

Turning to FIG. 6, a new assembly for a wheel restraint (700) is shown.It includes at least one new hub cap (708) (retainer bolts not shown forclarity of the drawing), an optional new or standard dust cap (707)(retainer bolts not shown for clarity of the drawing). The new hub cap(708) preferably has a hole formed in the center of it to receive anattachment end, such as a threaded bolt, of a restraint cable assembly(outer-end retention nut(s) not shown for clarity of the drawing).Attached to an inner end of the attachment end is a length of wire rope(703), a connector (702), and an inline bearing swivel (701). On theopposite end of the swivel (702) is preferably a similar series ofcomponents (702′, 703′, 704′, 708′, and various nuts, pins, etc., notshown for drawing clarity).

For a typical semi-trailer, a particular embodiment might be specifiedfor a 5,000 pound steady load (during wheel bearing failure), with a25,000 pound surge, so one might utilize Style TTS threaded studs(available from Hanes Supply, Inc., of Buffalo N.Y.), two lengths of ½″7×7 stainless steel wire rope (type 302/304, available from The CableConnection™ of Carson, Nev.), a bullet-style bearing swivel having lessthan 4″ outer diameter (available from The Crosby Group LLC of Tulsa,Okla.), and two stainless steel connectors to attach the wire rope tothe swivel in an appropriate manner (Holerite™ sockets available fromESCO Corporation of Portland, Oreg.). The overall length (710) of theretainer system (700) should be sized to match the length of theintended axle for protection. The cable connections can be swaged orswageless, and the cable can be replaced with other suitable, flexiblecomponents, such as but not limited to lengths of chain. Parts of theassembly may be coated in a plastic to protect the components frommetal-to-metal impacts, and from exposure to grease, oil, etc.

Referring now to FIG. 1, the wheel restraint system (700) can beinstalled on a hollow axle without removing the wheels, without removingthe load in the trailer, and conveniently in a truck lot withoutrequiring a mechanic's garage. The existing dust covers and hub caps onboth wheels at opposite ends of the axle are removed, such as byremoving a plurality of fastening bolts through a peripheral flange.After the open ends of the hollow axle are exposed, one threaded bolt ona first end (704′) can be fished into and through the hollow core of theaxle until it reaches the opposite end of the axle. This can be donemany ways, such as by taping the first end to a rod which is greaterthan the length of the axle, and then pushing the rod into and throughthe hollow core, pulling the taped end (704′), cables and swivel intothe hollow core with it.

At the opposite end, the threaded bolt can be affixed to the new hub cap(707) by passing the threaded bolt through the hole in the new hub cap(707), and securing it, such as with one or more washers, nuts, pins,retainer clips, etc. Now, the second end with the second threaded bold(704) remains at the originating end of the axle. A second new hub cap(707) is attached to the second end (704), such as with one or morewashers, nuts, pins, retainer clips, etc., keeping tension in the wheelrestraint system light for now. The two new hub caps (707) can now befastened to the hub assembly, such as by re-installing a plurality ofbolts, and torqued to specifications. The entire wheel restrain system(700) is now encased within the hollow core axle and spindles, exceptfor the tips of the threaded studs (704, 704′) and fasteners exposedoutside the new hub caps (707).

Now, in a preferred embodiment, tension is applied to the wheel restrainsystem (700) by pulling on the exposed tips of the threaded studs, andtightening the fasteners to take up the slack. The pulling tension canbe applied in a number of manners, such as by using a threaded tool toengage the bolts and provide for a manual pull handle, or by holding thetip of the threaded stud steady while rotating the fastening nut with awrench. It should be noted that the tension being applied is merely fortaking out the slack in the retainer system, but the tension is notnecessarily great enough to retain the wheels during a wheel bearingfailure. Finally, the optional dust caps (708) are installed on bothwheels, and installation is complete in just a few minutes.

During a wheel bearing failure, the movement (601) of the loose wheelassembly (600) will be restricted to stay near the end of the axle,thereby preventing the loose wheel assembly (600) from flying free fromthe moving truck. This failed wheel will now likely cause sparks, smokeand/or vibration which will be noticeable by the driver and/orpassersby, allowing the driver to bring the rig to a safe stop, keepingthe loose wheel assembly with or nearby the end of the axle.

CONCLUSION

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof, unless specifically stated otherwise.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

It will be readily recognized by those skilled in the art that theforegoing example embodiments do not define the extent or scope of thepresent invention, but instead are provided as illustrations of how tomake and use at least one embodiment of the invention. The followingclaims define the extent and scope of at least one invention disclosedherein.

What is claimed is:
 1. A wheel restraint system comprising: a firstattachment device for affixing to a first hub cap of a first end of anaxle and a first wheel assembly; a second attachment device for affixingto a second hub cap of a second end of the axle and a second wheelassembly; at least one inline swivel, having an exterior dimension lessthan an interior dimension of a hollow core of the axle; a first sectionof flexible retainer extending from the first attachment device to afirst end of the inline swivel, for reception into the hollow core ofthe axle; and a second section of flexible retainer extending from thesecond attachment device to a second end of the inline swivel, forreception into the hollow core of the axle.
 2. The wheel restraintsystem as set forth in claim 1 wherein the first attachment devicecomprises a threaded stud.
 3. The wheel restraint system as set forth inclaim 1 wherein the second attachment device comprises a threaded stud.4. The wheel restraint system as set forth in claim 1 wherein the firstsection of flexible retainer comprises a section of wire rope.
 5. Thewheel restraint system as set forth in claim 1 wherein the secondsection of flexible retainer comprises a section of wire rope.
 6. Thewheel restraint system as set forth in claim 1 wherein the first sectionof flexible retainer comprises a section of chain.
 7. The wheelrestraint system as set forth in claim 1 wherein the second section offlexible retainer comprises a section of chain.
 8. The wheel restraintsystem as set forth in claim 1 wherein the inline swivel comprises abullet-style bearing swivel.
 9. A method of manufacture a wheelrestraint system comprising: assembling a first section of flexibleretainer to extend from a first attachment device to a first end of aninline swivel for reception into the hollow core of an axle, wherein thefirst attachment device is configured to affix to a first hub cap of afirst end of an axle proximal to a first wheel assembly; and assemblinga second section of flexible retainer extending from a second attachmentdevice to a second end of the inline swivel, wherein the secondattachment device is configured to affix to a second hub cap of a secondend of the axle proximal to a second wheel assembly; wherein the inlineswivel has an exterior dimension less than an interior dimension of ahollow core of the axle.
 10. The method of manufacture as set forth inclaim 9 wherein the first attachment device comprises a threaded stud.11. The method of manufacture as set forth in claim 9 wherein the secondattachment device comprises a threaded stud.
 12. The method ofmanufacture as set forth in claim 9 wherein the first section offlexible retainer comprises a section of wire rope.
 13. The method ofmanufacture as set forth in claim 9 wherein the second section offlexible retainer comprises a section of wire rope.
 14. The method ofmanufacture as set forth in claim 9 wherein the first section offlexible retainer comprises a section of chain.
 15. The method ofmanufacture as set forth in claim 9 wherein the second section offlexible retainer comprises a section of chain.
 16. The method ofmanufacture as set forth in claim 9 wherein the inline swivel comprisesa bullet-style bearing swivel.